Quick answer: Good TB-500 testing starts with identity. TB-500 (Thymosin Beta-4) is a 43-amino-acid peptide, so its Certificate of Analysis should show a mass that matches the full-length sequence, not a short fragment. A high HPLC purity number is useful, but only after the mass confirms you have the right molecule.

What does TB-500 testing need to confirm?

Three questions matter for this compound. Is it the right molecule? How much of the vial contents is that molecule? And is the batch you hold the batch that was tested?

Our TB500 (Thymosin Beta-4) 10mg product page lists two tests: HPLC for chromatographic purity and mass spectrometry for molecular mass and identity. The sections below explain how to read each one for this peptide. For the general layout of a report, see our line-by-line COA guide.

Why is mass the most important TB-500 check?

The name "TB-500" is used loosely across the market. Our product page describes it as a synthetic peptide that mirrors the natural 43-amino-acid protein, also called Thymosin Beta-4, TB-4 or Tβ4. Some sellers use the same name for much shorter pieces of that sequence. For naming background, see our TB4 vs TB500 article.

Mass spectrometry settles the question. A full-length 43-residue peptide has a mass of roughly 5,000 daltons (about 4.96 kDa). A short fragment weighs far less, under 1,000 daltons. HPLC cannot tell these apart on its own, because both can look like one clean peak.

What HPLC purity can and cannot tell you

HPLC separates a sample into components and reports the main peak as a percentage of the total. Our page states purity above 99%. For a 43-amino-acid peptide, that number depends on the method. Closely related by-products, such as chains missing one amino acid, can sit almost on top of the main peak. A steeper gradient may hide them and a shallower one may reveal them.

So read the chromatogram, not just the headline figure. Look for a clear main peak, a stated detection wavelength and visible baseline.

Which problems are specific to a peptide like TB-500?

• Fragment substitution. A mass far below 5 kDa means the wrong, shorter molecule.
• Methionine oxidation. The sequence contains a methionine, which can pick up an oxygen atom. That shows as a second mass about 16 daltons above the main one.
• Acetylation. Natural Thymosin Beta-4 carries an acetyl group on its first amino acid, adding about 42 daltons. Check which form the report's theoretical mass reflects, and that the observed mass matches it.
• Truncated chains. Long syntheses can produce shorter by-products. These appear as smaller masses or as shoulders on the HPLC peak.

What is in the BioPure TB500 vial?

The product is TB500 (Thymosin Beta-4) in a 10mg size, supplied as a lyophilized (freeze-dried) powder. Our peptides are synthesized at a WHO/GMP and ISO 9001 certified laboratory in California. For why the powder form matters for stability, see our lyophilization explainer.

The vial label states 10mg. A purity percentage does not tell you the quantity in the vial, so check whether a report also gives a quantity figure. The product page lists HPLC and mass spectrometry only, so ask us what a specific batch report includes.

A TB-500 COA checklist

1. The compound name and sequence length (43 amino acids) are stated.
2. A theoretical mass and an observed mass are both shown, and they agree.
3. No unexplained secondary mass at about +16 daltons.
4. An HPLC trace is included, with a named method and a purity percentage.
5. The batch number matches your vial label.
6. The testing laboratory and date are named.

This product is sold for laboratory research use only.

Frequently asked questions

What molecular weight should a TB-500 report show?

For the full 43-amino-acid peptide, expect roughly 4.96 kDa. Compare the observed mass with the theoretical mass printed on the same report.

Is 99% purity enough on a TB-500 COA?

Not by itself. Purity describes how much of the sample is one species, not whether that species is the right one. Confirm the mass first.

What does a peak 16 daltons above the main mass mean?

It usually points to oxidation of the methionine in the sequence. A small amount of this by-product is a recognized issue for peptides containing methionine.

Is TB-500 the same as Thymosin Beta-4 on a COA?

Our product page describes TB-500 as a synthetic peptide mirroring the natural 43-amino-acid protein. The report should show a mass consistent with that length.

How is each batch of BioPure TB-500 tested?

The product page states that every batch undergoes third-party testing, using HPLC for purity and mass spectrometry for identity.

How do I know a COA belongs to my vial?

Match the batch or lot number on the report to the number on your vial label. If they differ, ask for the correct report before relying on it.

All products sold by BioPure Peptides are intended strictly for in-vitro laboratory and research use only. They are not for human or animal consumption. These statements have not been evaluated by the U.S. Food and Drug Administration, and these products are not intended to diagnose, treat, cure, or prevent any disease.